A combined superconducting coil is proposed for the purpose of increasing the strength of magnetic fields generated by large scale superconducting magnets where alloy type (NbTi) wires of the fully stabilized type is utilized as main windings. The coil is provided by numbers of high field composite superconducting wires produced by the compound type (Nb
3Sn, V
3Ga) material which are arranged as partial by-passes of the exciting current in regions exposed to strong magnetic field higher than the critical value of the superconducting material of the main windings. The arrangements of the high field wires are made in such a manner as they are in tight contact with (parallel type) or in place of (series type) the portions of the main windings in the respective turns in the high field regions. In either type, the Joule heat is generated by the current flowing through the normal conducting matrices of the connecting regions, and this heat is removed by the cryogenic Helium directly contacting with the winding surfaces. The amount of this excessive heat loss is in the range of 1kW-10kW for the large scale (10
10-10
13J) magnet practically used in the fusion reactors or the energy storage devices where the average field is about 8T and the maximum field is in the range of 14-17T.
抄録全体を表示